Smith Norm D, Schulze-Hoepfner Frank Thilo, Veliceasa Dorina, Filleur Stephanie, Shareef Sarah, Huang Lijun, Huang Xue-Mei, Volpert Olga V
Department of Urology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, USA.
J Urol. 2008 Jun;179(6):2427-34. doi: 10.1016/j.juro.2008.01.081. Epub 2008 Apr 23.
PEDF (pigment epithelium-derived factor) promotes the differentiation and survival of neuronal cells, and expands the adult neuronal stem cell niche. In the prostate PEDF is suppressed by androgen with unclear physiological consequences. We report that PEDF induced the neuroendocrine differentiation of prostate cancer cells, which was accompanied by neurite outgrowth and chromogranin A expression.
We performed neuroendocrine differentiation assay, Western blot analysis, immunostaining and reverse transcriptase-polymerase chain reaction in the human prostate cancer cell lines LNCaP, PC-3 and DU145, and the prostate epithelial strain RWPE-1 (ATCC).
Ectopic and endogenous PEDF caused neuroendocrine differentiation of prostate cancer cells, as manifested by neurite-like outgrowths and chromogranin A expression. The transdifferentiated cells expressed axonal and dendritic markers, as ascertained by immunoblotting for specific markers. Neuroendocrine cells formed multiple synaptophysin positive protrusions resembling dendritic spines and vesicles containing serotonin, pointing to possible synapse formation. The known transdifferentiating agent interleukin-6 induced PEDF secretion. Moreover, PEDF neutralizing antibodies abolished the transdifferentiation of interleukin-6 treated cells, suggesting an autocrine loop. Neurogenic events were independent of cyclic adenosine monophosphate. Instead, PEDF activated in this order RhoA, nuclear factor kappaB and Stat3. Inhibitors of the Rho, nuclear factor kappaB and STAT pathways abolished differentiation and synapse formation. Additionally, nuclear factor kappaB activation caused interleukin-6 expression.
We discovered that nuclear factor kappaB controls the formation of neuronal communications in the prostate due to PEDF. We defined a feed-forward loop, in which nuclear factor kappaB induction elicits Stat3 activation and pro-differentiating interleukin-6 expression causes the further expansion of neuroendocrine communications. Our findings point to the role of nuclear factor kappaB and PEDF in coordinated prostate development.
色素上皮衍生因子（PEDF）可促进神经元细胞的分化和存活，并扩大成年神经干细胞龛。在前列腺中，PEDF受雄激素抑制，其生理后果尚不清楚。我们报告称，PEDF可诱导前列腺癌细胞发生神经内分泌分化，同时伴有神经突生长和嗜铬粒蛋白A表达。
我们在人前列腺癌细胞系LNCaP、PC-3和DU145以及前列腺上皮细胞系RWPE-1（美国典型培养物保藏中心）中进行了神经内分泌分化测定、蛋白质印迹分析、免疫染色和逆转录聚合酶链反应。
异位和内源性PEDF均可导致前列腺癌细胞发生神经内分泌分化，表现为神经突样生长和嗜铬粒蛋白A表达。通过对特定标志物进行免疫印迹确定，转分化细胞表达轴突和树突标志物。神经内分泌细胞形成多个突触素阳性突起，类似于树突棘和含有5-羟色胺的囊泡，表明可能形成突触。已知的转分化因子白细胞介素-6可诱导PEDF分泌。此外，PEDF中和抗体可消除白细胞介素-6处理细胞的转分化，提示存在自分泌环。神经发生事件与环磷酸腺苷无关。相反，PEDF依次激活RhoA、核因子κB和信号转导及转录激活因子3（Stat3）。Rho、核因子κB和信号转导及转录激活因子3信号通路的抑制剂可消除分化和突触形成。此外，核因子κB激活可导致白细胞介素-6表达。
我们发现核因子κB由于PEDF而控制前列腺中神经元通讯的形成。我们定义了一个前馈环，其中核因子κB的诱导引发Stat3激活，促分化白细胞介素-6的表达导致神经内分泌通讯的进一步扩展。我们的研究结果表明核因子κB和PEDF在前列腺协调发育中的作用。
